1. Field of the Invention
The present invention relates generally to footwear incorporating lighting circuitry, and more particularly to an article of footwear incorporating a multiple-switch controlled lighting circuit for improving battery life.
2. Description of the Prior Art
Footwear incorporating lighting elements is well known in the art. The simplest such devices, as exemplified by U.S. Pat. Nos. 3,893,247 and 3,946,505, disclose shoes having lighting elements disposed in the heel and/or sole. The battery and lighting circuitry are disposed in a removable heel. A manual switch is provided for turning the lighting element on and off. A tilt switch is also provided for turning the light on and off responsive to the position of the shoe. Unfortunately, this tilt switch can become a disadvantage if the shoe is accidentally stored in a tilted position which could cause the battery to drain and prematurely discharge.
U.S. Pat. No. 4,158,922 discloses a shoe having a single lighting element incorporated in the heel. An oscillator is provided for causing continuous periodic flashing of the single light. A mechanical switch and/or a tilt switch may be included for activating the oscillating circuit.
In such prior art devices, the lighting element is turned on either manually or by a mercury switch. If the switch is left on, or the shoe is left at the wrong orientation, the light continues to operate draining power from the battery which prematurely discharges.
In an effort to overcome this problem with the prior art, U.S. Pat. No. 4,848,009, discloses an article of footwear provided with a battery, a light source, a motion responsive switch to intermittently connect the battery to the light source, and a timing circuit which is provided for extinguishing the light after a predetermined amount of time. However, such a timing circuit can unduly complicate the design and, moreover, can prematurely extinguish the light before the total desired effect is obtained by the wearer.
The disadvantages of the prior art are overcome by the present invention which extends the battery life in such footwear without the need for a timing circuit and which permits the wearer to dynamically control the operation of the lights depending on the movement of the foot while preventing inadvertent discharge of the battery regardless of the orientation in which the shoe is left when not being worn.